I'm working on developing custom rules for my team with Schematron. I'm trying to start off with a simple--but relevant--rule. I followed oXygen's help to create a custom framework and add my custom schema. I have confirmed that I did this successfully and my schema is applied to validation.

However, I am not getting my error reported. I've tried several versions of my rule.

I'm at my wit's end because all training materials I've double checked have indicated that Version #1 should have worked. I checked oXygen's examples of your schematron rules, which is why I tried Version #2 instead (I noticed yours were always using the class attribute), but then that didn't work either.

went back and manually validated the DITA topic and the image was highlighted with an error marker.
So it works for me. It's probably something on your side causing the Schematron not to be applied on the topic.
On the Oxygen XML blog there is a recommendation about sharing Schematron rules:

The culprit turned out to be a duplicate copy of my schema that I didn't know was in my framework file. With your confirmation that my code was correct, I went through the steps for extending the framework again and found the errant file. When I deleted it and reconfigured my settings, my schema worked. I added the quick fix component and that also worked.